Pavement markings (e.g., paints, tapes, and individually mounted articles) guide and direct motorists and pedestrians traveling along roadways and paths. Paint was a preferred pavement marking for many years. However, modern liquid pavement marking materials offer significant advantages over paint, such as increased visibility, retroreflectance, improved durability, and temporary and/or removable marking options.
For example, pavement markers made with liquid pavement marking materials may include reflective optical elements adhered to the pavement surface. Liquid pavement markings can use glass microspheres for retroreflection. The microspheres can be flood coated onto the wet liquid pavement marking material after coating. This provides the liquid pavement marking material with improved retroreflectivity and also covers the top surface of the uncured or undried coating with a protective layer of microspheres. This protective layer can allow the markings to be exposed to traffic sooner because of the layer of microspheres over the surface, which prevents transfer of the coating to the surface of vehicle tires. The time between application and the point where material will no longer transfer to vehicle tires is defined as the “track-free” time. Shorter track-free times increase marking efficiency by reducing or eliminating the need for traffic disruption through such measures as closing lanes or placing traffic control devices to protect such markings.